1. Field of the Invention
The present invention relates to an imaging system capable of improving the quality of image data obtained by imaging an optical image of a subject, an imaging apparatus including the imaging system, a portable terminal apparatus including the imaging system, an onboard apparatus including the imaging system, a medical apparatus including the imaging system, and a method for manufacturing an imaging system.
2. Description of Related Art
An imaging system that forms an optical image of a subject, which is focused on a light receiving surface through an imaging lens, by utilizing an imaging device, such as a CCD or a CMOS device, having the light receiving surface on which a plurality of light receiving pixels are two-dimensionally arrayed is known.
As an example of such an imaging system, an onboard camera or a portable cellular phone camera in which an imaging system having an imaging lens designed such that the depth of field increases is attached directly on a circuit board has already put to practical use (refer to JP-A-2007-147951). In addition, an onboard camera or a portable cellular phone camera with high performance in which an imaging system, in which the number of light receiving pixels of an imaging device is increased and the resolving power of an imaging lens is improved, is mounted is also known. Among such onboard cameras or portable cellular phone cameras with high performance capable of obtaining high-resolution images, one in which the resolving power of an imaging lens is close to a diffraction limited is also known.
However, in manufacturing an imaging system having such an imaging lens capable of forming an image with high resolution, it is difficult to increase the yield due to difficulties in manufacture. That is, since image data allowing an image having an intended resolution to be formed cannot be generated, there is a possibility that many imaging systems will be out of a production line for readjustment or reassembly. In addition, an imaging system removed from the production line is reproduced such that and image data capable of forming an image with the intended resolution can be generated by specifying the cause and performing modification.
However, there are various causes of reducing the resolution of an image expressed by image data output from an imaging system. For example, various causes, such as shape errors (surface shape error, thickness error, and eccentric error of a lens) of an individual lens used to form an imaging lens, assembly and adjustment errors of an imaging lens (shift error and tilt error of a lens and air space error between lenses), and a positional error of an imaging device with respect to an imaging lens, may be considered. For this reason, there is a problem that a cost is significantly increased for reproduction to an imaging system capable of generating high-quality image data, which allows an image with the intended resolution to be formed, by specifying a cause of the reduction in resolution and performing readjustment and reassembly.